Fine-grained locking for POSIX local sockets (UNIX domain sockets)

Maxim Sobolev sobomax at
Tue May 9 01:24:24 UTC 2006

Kris Kennaway wrote:
> On Mon, May 08, 2006 at 06:18:18PM -0700, Maxim Sobolev wrote:
>> Kris Kennaway wrote:
>>> On Mon, May 08, 2006 at 02:52:07AM -0400, Kris Kennaway wrote:
>>>> OK, David's patch fixes the umtx thundering herd (and seems to give a
>>>> 4-6% boost).  I also fixed a thundering herd in FILEDESC_UNLOCK (which
>>>> was also waking up 2-7 CPUs at once about 30% of the time) by doing
>>>> s/wakeup/wakeup_one/.  This did not seem to give a performance impact
>>>> on this test though.
>>> Turning down kern.hz from 1000 to 100 also made a big difference on 12
>>> CPUs (+6.1%).
>>> Note also that the system is no less than 40% idle during the runs (at
>>> any load), so the bottlenecks are serious.
>> Maybe HDD just can't keep up with the pace?
> There is no disk I/O involved.

Oh, sorry.


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